HELPPPPP!!!!! Lost iMovie project!!!!!

I just finished a REALLY important project for school on iMovie and I exported it using Quicktime to see how large the file would be (it needed to be under 20KB) and when I went back to make a few edits my file was choppy so I quit and restarted iMovie. When it reopened again my project was gone! And now I cannot find it! Ack! Help! This is three weeks worth of work and I have no idea how to find/retrieve it! PLEASE, PLEASE HELP!!!!!!!!

wonder who started this "hit the new guy over the head" business good 1 Clay ... I just have to find some1 to rep b4 I rep you again

lol Really wasn't trying to beat him up . Just believe no one would work on something that important for 3 weeks without a back up , so really was trying to make a good suggestion . Now if there is no back-up then.....